The electronics industry has experienced an ever increasing demand for smaller and faster electronic devices which are simultaneously able to support a greater number of increasingly complex and sophisticated functions. Accordingly, there is a continuing trend in the semiconductor industry to manufacture low-cost, high-performance, and low-power integrated circuits (ICs). Thus far these goals have been achieved in large part by scaling down semiconductor IC dimensions (e.g., minimum feature size) and thereby improving production efficiency and lowering associated costs. However, such scaling has also introduced increased complexity to the semiconductor manufacturing process. Thus, the realization of continued advances in semiconductor ICs and devices calls for similar advances in semiconductor manufacturing processes and technology.
As merely one example, semiconductor lithography processes may use lithographic templates (e.g., photomasks or reticles) to optically transfer patterns onto a substrate. Such a process may be accomplished, for example, by projection of a radiation source, through an intervening photomask or reticle, onto the substrate having a photosensitive material (e.g., photoresist) coating. The minimum feature size that may be patterned by way of such a lithography process is limited by the wavelength of the projected radiation source. In view of this, extreme ultraviolet (EUV) radiation sources and lithographic processes have been introduced. However, EUV systems, which utilize reflective rather than conventional refractive optics, are very sensitive to contamination issues. In one example, particle contamination introduced onto a reflective EUV mask can result in significant degradation of the lithographically transferred pattern. As such, it is necessary to provide a pellicle membrane over an EUV mask, to serve as a protective cover which protects the EUV mask from damage and/or contaminant particles. Additionally, to avoid a drop is reflectivity, it is important to use a thin, high-transmission material as the pellicle membrane. However, the fabrication of large, thin pellicle membranes according to certain conventional fabrication processes may cause the pellicle membrane to become distorted, wrinkled, broken, or otherwise damaged, thereby rendering the pellicle membrane unusable. Thus, existing EUV mask pellicle fabrication techniques have not proved entirely satisfactory in all respects.